Ventilating systems are commonly used to maintain environmental standards in industrial, commercial and farming facilities, such as foundries, factories, metal finishing areas, workshops, service areas, warehouses, metting halls, recreational buildings, animal, nursery and feeder houses and other facilities of many diverse types. Ventilation systems for such facilities are necessary to remove excess heat, discharge pollutants and to maintain a healthful comfortable environment. Unfortunately, safety, health and economic consideration are at odds with one another in that air which has been heated or colled at substantial expense is virtually thrown away by the conventional ventilation process. In the case of a heated facility, the exhaust air in the ventilation process contains not only the sensible energy expended in increasing the supply air temperature but the latent energy represented by the vaporized water required to adequately humidify. With great pressure on power producing utilities and the ever-increasing cost of fuels for heating and cooling, there is a great need to recover thermal energy from the exhaust air of all high performance ventilation systems.
One approach to thermal energy recovery in ventilation systems is disclosed in my patent application U.S. Ser. No. 600,620 filed July 31, 1975, now U.S. Pat. No. 4,049,404. That invention provided a low-cost, high performance ventilation system capable of supplying air to and exhausting air from a temperature-controlled area in a unidirectional flow pattern at approximately 8000 cubic feet per minute while at the same time recovering an extremely high percentage of thermal energy, both sensible and latent from exhausted air. The invention makes possible a unit of low initial cost which can be offset in fuel savings in a very short time in which waste heat, such as from lighting, motors and like devices is utilized and in which a unidirectional flow pattern through the work area maintains desired temperatures from floor to ceiling. The present invention represents an improvement over the subject matter of U.S. Ser. No. 600,620, now U.S. Pat. No. 4,049,404.
Prior art thermal energy recovery ventilating systems typically were designed for extremely large commercial buildings such as assembly plants, foundries, warehouses and the like and comprised several large housings which had to be interconnected with duct work. These housings typically were extremely heavy and required elaborate foundations and supports which had to be integrated ahead of time into the building's superstructure and occupied a substantial amount of roof space. Additionally, heavy construction equipment such as cranes were necessary to lift the housings to the roof. These systems were also relatively costly, not only to purchase but to interface with the existing structure and many manhours of labor were required to interconnect the necessary duct work and electrical wiring. It would be advantageous to have an energy-conserving ventilation system which was lightweight, compact in a single unit containing the matrices, valve and fans which could be applied to relatively smaller temperature controlled structures which heretofore found the prior art systems economically unfeasible. It is to this area that the present invention is directed.